Fluorescence spectroscopy of excitation transfer in Photosystem 1
This thesis centers on the study of excitation transfer in a photosynthetic antenna array. The spectroscopic properties of two pigment-protein complexes were investigated. These complexes, isolated from higher plants, display an unusual temperature dependent fluorescence behavior. The author have chosen to study this fluorescence behavior with respect to energy transfer to the reaction center and in an isolated intact antenna preparation. A Photosystem 1 complex, PSI-200, was isolated from spinach. We have characterized this system by both steady state and time-resolved fluorescence spectroscopy. Fluorescence polarization measurements indicate that this emission arises from pigments which absorb in the long wavelength region of the spectrum and comprise a relatively small portion of the antenna population. Comparison of spectral characteristics were made with a PSI complex isolated from the thermophilic cyanobacterium, Synechococcus, sp. To address the role of Chl b in stimulating long wavelength fluorescence and the temperature dependence of the system, we have studied the energy transfer dynamics in an antenna complex, LHC-I isolated from PSI-200. Kinetic measurements indicate that initially absorbed excitation is rapidly redistributed to longer wavelength emitting pigments within 40 ps. The temperature dependence of F685 results from increased back transfer from long wavelength emitters to F685. We suggest that changes in excitation transfer between the various emitting species and a non-radiative fluorescence quenching mechanism account for the temperature dependence of the system. 144 refs., 50 figs., 3 tabs.
- Research Organization:
- Lawrence Berkeley Lab., CA (USA)
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (USA)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 5871906
- Report Number(s):
- LBL-30136; ON: DE91011867
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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Spectroscopic studies of energy transfer in photosynthetic reaction centers of higher plants
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Related Subjects
PHOTOSYNTHETIC REACTION CENTERS
ENERGY TRANSFER
COMPARATIVE EVALUATIONS
CYANOBACTERIA
EXPERIMENTAL DATA
FLUORESCENCE SPECTROSCOPY
SPINACH
TEMPERATURE DEPENDENCE
DATA
EMISSION SPECTROSCOPY
FOOD
INFORMATION
MAGNOLIOPHYTA
MAGNOLIOPSIDA
MICROORGANISMS
NUMERICAL DATA
PLANTS
SPECTROSCOPY
VEGETABLES
550200* - Biochemistry